hi guys, currently im building a passband system of 5 GHz, so I have simulated 16 QAM and its perfectly working fine at 5 GHz.

But I am very new to OFDM, I have been studying on the background of OFDM and all of them only talking about baseband OFDM. Im not interested with using the MATLAB function to generate baseband 16-QAM, cause I have to analyse the changes of BER and EVM with changes of frequency.

So my question is, the generated 16 QAM signal are not in complex value, cause I have summed the I and Q channel at the end, so from the summation of this I and Q channel, I actually got the 16 QAM signal which is very trivial.

Then I have to shift from serial to parallel before performing IFFT in OFDM, but my question is, my signal is not complex, how could I IFFT my signal? should I FFT after the serial to parallel conversion and IFFT back again, but it doesnt make sense.